Seigniorage is central bank's income from the issue of currency. In the case of the NBP, the amount of seigniorage is limited by the chronic excess liquidity existing in the banking system. The situation forces the Polish central bank to undertake costly open market operations in order to maintain interest rates at the desired level. In the last few years, the costs of these sterilising operations have amounted to several billion zloty, seriously eroding NBP's income.

This might change, should the Bank manage to introduce operational liquidity shortage to the Polish banking sector. Open market operations would then contribute to NBP's income instead of reducing it. Unfortunately, such a change is not very likely to occur in the nearest future.

Following Poland's accession to the Economic and Monetary Union, the NBP's seigniorage income will be partially disposed of by the European Central Bank. The ECB divides the funds thus procured in proportion to the respective central banks' contributions to ECU's equity.

Over time, as the general demand for cash in the economy declines and commercial banks hold less funds on account at the central bank, the significance of seigniorage as the source of government revenue will diminish.